Photodynamic Treatment of Yeast With Chloroaluminum‐phthalocyanine: Role of the Monomeric Form of the Dye

Abstract

The effect of photodynamic treatment on the yeast Kluyveromyces marxianus with aluminum‐phthalocyanines has been studied. It was found that the nonsulfonated sensitizer caused light‐dependent loss of colony‐forming capacity, whereas the mono‐ and tetrasulfonated forms did not induce loss of clonogenicity. The effect of the nonsulfonated sensitizer increased with longer preincubation periods of cells with the dye. Formation of cellattached, mostly intracellularly localized monomelic sensitizer also increased with time. The amount of cell‐bound multimeric nonsulfonated phthalocyanine did not vary with time. Experiments designed to specifically increase the amount of cell‐attached monomers led also to an increased photoinactivation of the cells. It is therefore concluded that the photodynamic effect of the nonsulfonated Al‐phthalocyanine is mediated by the monomeric form of the dye.

In Vitro Photodynamic Inactivation of Cryptococcus neoformans Melanized Cells with Chloroaluminum Phthalocyanine Nanoemulsion

“…It was found that treatment with mono‐ and tetrasulphonated aluminum‐Pc did not induce loss of clonogenicity whereas treatment with chloroaluminum caused a light‐dependent loss of colony‐forming capacity. The photodynamic effect of the nonsulphonated ClAlPc was mediated by the monomeric form of the dye (34). PDT with ClAlPc led to several forms of cellular damage, such as potassium leakage, inhibition of enzymes involved in energy metabolism and protein synthesis but only inhibition of protein synthesis was considered a critical factor contributing to the loss of clonogenicity (35).…”

A comprehensive overview of photodynamic therapy in the treatment of superficial fungal infections of the skin

“…Mutagenic effects of photodynamic treatment with ClAl-Pc and RPL068 were not found in K. marxianus [24] and C. albicans [30].…”

“…Prolonged irradiation causes the additional alteration of other cytoplasmic structures and the inhibition of the synthesis of DNA and RNA [24], but genotoxic and mutagenic effects were never detected in yeasts [22].…”

Photodynamic therapy against achromic M6 melanocytes: phototoxicity of lipophilic axially substituted aluminum phthalocyanines and hexadecahalogenated zinc phthalocyanines

“…We already obtained good photodynamic effect with lipophilic aluminum phthalocyanines [9,10], but macrocycles such as porphyrins and phthalocyanines form aggregates in solution which usually shorten the electronically excited state lifetime by enhancement of internal conversion [11,12] and depress their photosensitizing power [13] since the more active form of the dye is monomeric [14,15]. In this work, we added bulky ligands on the metal in order to reduce and/or cancel aggregation.…”

“…Expressing a preferential interaction with the malignant cells [22], LDLs have been proposed as tumorspecific vehicles of systemically injected photosensitizers [23,24]. Finally, PDT against cell lines and tumors using hydrophilic sulfonated aluminum phthalocyanines has been largely investigated but, to our knowledge, few studies have been performed on lipophilic ones [14,15,[25][26][27][28].…”